Author of the first English dentistry text book in 1685 - The Operator For The Teeth.
The Operator For The Teeth is the first book on dentistry published in the English language. There are two known copies, one in the library of York Minster, and the other is in the library of the College of Dentistry of New York University. New editions were published in 1686 and 1687
Unfortunately, almost nothing is known about Charles Allen, except that in 1685 he was "at his lodging at Mr Galloway's Apthecary in Stonegate, York", and in 1686 he was "at his own lodging at Mr Bannister's at the Smith Arms in Essex Street", Dublin.
This Mr Galloway was Walter Galloway, who became a Freeman of York and a member of the Guild of Barber Surgeons of York in 1680. The book is available to read online at dentaljuce.com/dental-history. It explains that diseased gums can be prevented and cured by "regular removal of the scales", and gives advice on transplanting teeth using animals as donors:.
First I would choose an animal whose teeth should come nearest to those of the patient; as a Dog, a Sheep, a Goat, or a Baboon etc. and having tied his legs together, I would fasten his head in some convenient place, so that he might not stir in the least, and by some proper means keep his mouth open, as long as I should have occasion: that done, I would open the gums around the tooth to be taken out of his head, not only to the very jaw-bone, but as far between the said bone and the tooth, as the finest Instrument could go; leaving a very little portion of the gums about it, and then having used the same circumspection, in dividing the Patients tooth from the gums, and the Jaw-bone, I would draw it forth, and put immediately in its place that of the Brute,; fastening it very well and straight between the other teeth.
Text source: Ronald Cohen / Charles Allen